1. Field of the Invention
The present invention relates to a liquid discharge head and a method of manufacturing the same.
2. Description of the Related Art
In general, liquid discharge heads applied to an ink jet recording scheme are provided with fine liquid discharge ports, liquid flow paths, and plural energy generating elements which are provided on a portion of the liquid flow paths. Since the liquid flow paths and the liquid discharge ports have a fine structure, there is demand for a technique of manufacturing the structure with high accuracy. As such a technique, from the point of view of accuracy and ease of processing, a photolithography technique is employed.
Recently, in an ink jet recording scheme, in order to improve discharged liquid droplets precisely reaching a recording medium, the distance between the recording head and the recording medium has been significantly shortened. For this reason, the surface of the recording head comes into contact with the recording medium because of surface irregularities such as wrinkles on the recording medium or jamming of the recording medium. In the nozzle having the liquid discharge port formed by the above-mentioned photolithography technique, since the surface of the nozzle in the vicinity of the liquid discharge port is made of a resin material, the surface of the nozzle may be damaged due to contact with the recording medium in some cases. When the damage occurs in the vicinity (nozzle portion) of the liquid discharge port, a discharging direction of the discharging liquid droplet is deviated so as to cause deterioration in printing quality.
As a method of improving strength of the nozzle surface including the liquid discharge ports, there has been generally known a method in that a filler made of an inorganic oxide such as amorphous silica or a resin is added to a resin material so as to adjust a physical property of the resin material. For example, U.S. Pat. No. 5,510,818 discloses a method of manufacturing in an ink jet recording head by a transfer-molding forming method using an epoxy resin which is reduced in linear expansion coefficient by adding an inorganic filler.
As described above, by adding the inorganic fine particles to the resin material, an elastic modulus of the resin material can be increased and the mechanical strength thereof can be increased. However, when the inorganic fine particles are added to the resin material in order to increase the strength of the nozzle surface, the elastic modulus of the resin material is increased by the influence of the inorganic fine particles, and as a result, stress is also increased in some cases. When the stress is increased, there may be a problem in that deformation, cracking, and peeling of the material of the discharge ports occur.
In addition, particularly when a transparent photo-hardening resin is employed, the added inorganic fine particles influence the hardening property, so that it may cause deterioration in patterning property, for example, resolution and contrast, and deterioration in adhesiveness to the material in some cases.
In addition, as described above, the shape of the discharge ports can particularly influence the printing quality, and it is appropriate that the mechanical strength in the vicinity of the discharge ports is high.